JP7192408B2 - Hybrid vehicle control device - Google Patents

Description

The present invention relates to a control device for a hybrid vehicle equipped with an engine and a motor as power sources.

2. Description of the Related Art Conventionally, as a vehicle capable of appropriately controlling an engine speed and an output torque, a hybrid vehicle capable of controlling the engine speed by a motor and a vehicle equipped with a continuously variable transmission are known.

Patent Literature 1 describes such a hybrid vehicle, in which the engine speed is controlled by a first motor so as to operate the engine at the optimum fuel efficiency line. In addition, the hybrid vehicle described in Patent Document 1 is configured to change the operating point (or driving point) of the engine according to the driving intention of the driver. For example, when the degree of accelerator opening increases due to the driver's operation of the accelerator, or when the demand for agility is high, such as when the longitudinal or lateral acceleration increases, the engine operating point is changed to the high-torque side. is configured to In other words, the hybrid vehicle described in Patent Literature 1 is configured to appropriately control the operating point of the engine according to the driving intention of the driver.

WO2013/042177

As described above, according to the hybrid vehicle described in Patent Literature 1, by controlling the operating point of the engine, it is possible to drive with a focus on fuel efficiency or with a focus on driving inclination. On the other hand, a hybrid vehicle has a plurality of heat generating sources or heat generating parts in the transmission, and there is a possibility that the amount of heat generated in the transmission increases when the vehicle is driven with emphasis on fuel efficiency and driving intentions as described above. For example, there is a risk that the temperature of the motor that controls the engine speed will increase, or that heat generation will increase in the gear unit that constitutes the power split mechanism.

Such an increase in the amount of heat generated within the transmission reduces the durability of various devices and increases power loss. In order to suppress the heat generation, a new cooling mechanism is provided, or if the cooling performance is improved by changing the specifications of the currently installed cooling mechanism (for example, an oil cooler), cooling This may lead to an increase in the size of the mechanism and a significant increase in cost. Therefore, there is still room for improvement in suppressing the temperature rise in the transmission with the existing configuration without providing a new mechanism.

The present invention was conceived with a focus on the above technical problems, and it is possible to suppress excessive temperature rise in the transmission while satisfying drive requirements without improving the performance of the cooling mechanism. It is an object of the present invention to provide a control device for a hybrid vehicle that is more efficient.

In order to achieve the above object, the present invention includes an engine, a first motor, and a transmission for transmitting output torque of the engine to driving wheels, the transmission transmitting the output torque of the engine. at least three rotary elements: a first rotary element connected to the driving wheel, a second rotary element connected to the drive wheels so as to transmit torque, and a third rotary element to which torque is transmitted from the first motor. a control device for a hybrid vehicle configured to transmit the output torque of the engine to the driving wheels via the differential mechanism while cooling the inside of the transmission to perform HV running. and a controller for controlling the engine and the first motor, the controller controlling the operating point of the engine by controlling the rotation speed of the first motor , wherein the HV When a predetermined temperature parameter for determining the state of heat generation inside the transmission is lower than a predetermined temperature during running, the engine is operated at an operating point that maximizes the fuel efficiency of the engine. and controlling the rotation speed of the first motor, and reducing the amount of heat generated inside the transmission rather than the fuel consumption of the engine when the temperature parameter is equal to or higher than the predetermined temperature during the HV running. An operation of preferentially controlling the rotation speed of the first motor to a predetermined rotation speed range including 0 in which the heat generation can be suppressed, thereby reducing the heat generation at the operating point of the engine. A required power of the engine is obtained when controlling the operating point of the engine to an operating point that reduces the amount of heat generated , and whether or not the required power is equal to or greater than a predetermined threshold value. is determined, and when it is determined that the required power is equal to or greater than the threshold value, the operating point of the engine is reduced from the operating point at which the fuel efficiency is optimal while satisfying the required power. and, when it is determined that the output torque of the engine is increased and the required power is less than the threshold value, the operating point of the engine is changed to satisfy the required power while achieving the best fuel efficiency. The rotation speed of the engine is increased and the output torque of the engine is changed so as to decrease from the operating point where .

Further, in the present invention, the hybrid vehicle further includes a cooling mechanism for cooling the transmission and the engine, and the controller determines whether or not the temperature inside the transmission is equal to or higher than the predetermined temperature. The determination may be made based on the temperature of at least one of the temperature of the motor, the temperature of oil cooling the first motor and the differential mechanism, and the temperature of the cooling mechanism.

Further, in the present invention, the threshold value may be configured such that the value at a high vehicle speed is larger than the value at a predetermined vehicle speed.

According to the hybrid vehicle control apparatus of the present invention, the amount of heat generated in the transmission is reduced by controlling the operating point of the engine. Specifically, when the temperature inside the transmission is lower than a predetermined temperature, the engine is controlled along the well-known operating point (optimal fuel efficiency line) at which the fuel efficiency of the engine is optimal. On the contrary, when the temperature inside the transmission is equal to or higher than the predetermined temperature, the operating point of the engine is controlled to an operating point at which the amount of heat generated in the transmission is reduced. Therefore, when the temperature inside the transmission is relatively high, the operating point of the engine is controlled to an operating point at which the amount of heat generated is reduced, thereby suppressing an excessive rise in the temperature inside the transmission. In addition, since the temperature rise in the transmission can be suppressed in this way, there is no need to provide a new cooling mechanism or to improve the cooling performance of the currently installed cooling mechanism. , the cooling performance can be ensured, and the accompanying increase in cost can be suppressed or avoided.

Further, according to the present invention, by controlling the operating point of the engine as described above, the amount of heat generated in the transmission can be reduced, thereby reducing the power loss associated with the heat generation. Furthermore, the control of the operating point of the engine is configured to be controlled by the first motor, and in particular, the control of the engine for reducing the heat generation amount controls the rotation speed of the first motor 2 to a low rotation speed range. is configured as Therefore, it is possible to reduce the mechanical loss that depends on the number of revolutions of the first motor, and to reduce the accompanying power loss.

1 is a skeleton diagram showing an example of a hybrid vehicle targeted by the present invention; FIG. 4 is a flowchart for explaining an example of control in this embodiment of the vehicle; 1 is a map for explaining the operating line and operating points of an engine; 4 is a map for explaining an example of thermal efficiency of an engine;

Embodiments of the present invention will be described with reference to the drawings. It should be noted that the embodiment shown below is merely an example when the present invention is embodied, and does not limit the present invention.

FIG. 1 shows an example of a hybrid vehicle (hereinafter simply referred to as a vehicle) Ve to be controlled in an embodiment of the invention. The vehicle Ve includes an engine (ENG) 1, a first motor (MG1) 2, and a second motor (MG2) 3 as driving force sources. It is configured to be divided and transmitted to the first motor 2 side and the drive shaft 5 side. Further, the electric power generated by the first motor 2 is supplied to the second motor 3 so that the driving force output by the second motor 3 can be applied to the drive shaft 5 and the drive wheels 6 . Further, a transmission 7 is provided for transmitting the power of the engine 1 and the motors 2 and 3 to the drive wheels 6. The transmission 7 includes a transmission case 7a, the power split mechanism 4 accommodated in the transmission case 7a, and a counter. It is composed of various functional parts including a gear mechanism and a differential gear mechanism.

The engine 1 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine, and is configured such that its output is adjusted and operating conditions such as starting and stopping are electrically controlled. In the case of a gasoline engine, the opening of the throttle valve, the amount of fuel supplied or injected, execution and stop of ignition, ignition timing, etc. are electrically controlled. In the case of a diesel engine, the amount of fuel injection, the timing of fuel injection, or the opening of a throttle valve in an EGR (Exhaust Gas Recirculation) system is electrically controlled.

Both the first motor 2 and the second motor 3 function as motors that output torque when drive power is supplied, and function as generators that generate power when torque is applied (power generation function). That is, the first motor 2 and the second motor 3 are motors (so-called motor generators) having a power generation function, and are configured by, for example, permanent magnet synchronous motors or induction motors. The first motor 2 and the second motor 3 are electrically connected to a power storage device (both not shown) such as a battery or a capacitor via an inverter, and are supplied with electric power from the power storage device. Alternatively, it is configured so that the power storage device can be charged with the generated power.

The power split mechanism 4 is a transmission mechanism that transmits torque between the engine 1 and the first motor 2 and the drive wheels 6, and is composed of a planetary gear mechanism having a sun gear 8, a ring gear 9, and a carrier 10. . In the example shown in FIG. 1, a single pinion type planetary gear mechanism is used. A ring gear 9, which is an internal gear, is arranged concentrically with the sun gear 8, which is a planetary gear mechanism. A pinion gear 11 meshing with the sun gear 8 and ring gear 9 is held by a carrier 10 so as to rotate and revolve. The power split mechanism 4 corresponds to the "differential mechanism" in the embodiment of the invention, the carrier 10 corresponds to the "first rotating element" in the embodiment of the invention, and the ring gear 9 corresponds to the "differential mechanism" in the embodiment of the invention. It corresponds to the "second rotating element" in the embodiment, and the sun gear 8 corresponds to the "third rotating element" in the embodiment of this invention.

The power split device 4 is arranged on the same axis as the engine 1 and the first motor 2 . An output shaft 1 a of the engine 1 is connected to a carrier 10 of a planetary gear mechanism that constitutes the power split device 4 . The output shaft 1a of the engine 1 is coaxially connected to the input shaft 12 of the power split mechanism 4 in a power transmission path from the engine 1 to the driving wheels 6. As shown in FIG. Further, the carrier 10 is connected to the rotary shaft 13a of the oil pump 13 on the side opposite to the output shaft 1a of the engine 1. As shown in FIG. The oil pump 13 is provided for lubricating or cooling each part such as the motors 2 and 3 and the power split mechanism 4 . The oil pump 13 is an oil pump having a general configuration that is conventionally used in vehicles as a pump for supplying oil, and is configured, for example, to drive the oil pump 13 by the engine 1 to generate hydraulic pressure. It is

The first motor 2 is connected to the sun gear 8 of the planetary gear mechanism. The first motor 2 is arranged adjacent to the power split device 4 on the side opposite to the engine 1 (left side in FIG. 1). A rotor shaft 2 b that rotates integrally with the rotor 2 a of the first motor 2 is connected to the sun gear 8 . The rotating shafts of the rotor shaft 2b and the sun gear 8 are hollow shafts. A rotary shaft 13a of the oil pump 13 is arranged in a hollow portion of the rotary shafts of the rotor shaft 2b and the sun gear 8. As shown in FIG.

A first drive gear 14 which is an external gear is formed integrally with the ring gear 9 on the outer peripheral portion of the ring gear 9 of the planetary gear mechanism. A countershaft 15 is arranged parallel to the rotation axes of the power split device 4 and the first motor 2 . A counter driven gear 16 meshing with the first drive gear 14 is attached to one end (right side in FIG. 1) of the counter shaft 15 so as to rotate together. The counter driven gear 16 has a larger diameter than the first drive gear 14 and is configured to amplify torque transmitted from the first drive gear 14 . On the other hand, a counter drive gear 17 is attached to the other (left side in FIG. 1) end of the counter shaft 15 so as to rotate integrally with the counter shaft 15 . The counter drive gear 17 meshes with a differential ring gear 19 of a differential gear 18, which is a final reduction gear. Therefore, the ring gear 9 of the power split mechanism 4 is connected to the drive shaft 5 via an output gear train 20 consisting of the first drive gear 14, the counter shaft 15, the counter driven gear 16, the counter drive gear 17, and the differential ring gear 19. and drive wheels 6 so as to be able to transmit power.

Further, the vehicle Ve is configured such that the torque output by the second motor 3 can be added to the torque transmitted from the power split mechanism 4 to the drive shaft 5 and the drive wheels 6 . Specifically, a rotor shaft 3b that rotates integrally with the rotor 3a of the second motor 3 is arranged parallel to the countershaft 15 described above. A second drive gear 21 meshing with the counter driven gear 16 is attached to the tip (right end in FIG. 1) of the rotor shaft 3b so as to rotate together. Therefore, the second motor 3 is coupled to the ring gear 9 of the power split mechanism 4 via the differential ring gear 19 and the second drive gear 21 as described above so that power can be transmitted. That is, the ring gear 9 is coupled to the drive shaft 5 and the drive wheels 6 through the differential ring gear 19 together with the second motor 3 so that torque can be transmitted.

A radiator 22 is provided in the vicinity of the engine 1 for exchanging heat between cooling water and outside air to cool the cooling water. An oil cooler 23 is provided for cooling the oil supplied to the cooling target parts such as.

The hybrid vehicle Ve shown in FIG. 1 has an HV travel (hybrid travel) mode using an engine 1 as a power source, and an EV travel mode in which the first motor 2 and the second motor 3 are driven by the electric power of the power storage device. Can be set. Such setting and switching of each mode are executed by an electronic control unit (ECU) 24 .

The ECU 24 corresponds to the "controller" in the embodiment of the invention, and is electrically connected to transmit control command signals to the engine 1, the first motor 2, and the second motor 3, for example. The ECU 24 is mainly composed of a microcomputer, performs calculations using input data, pre-stored data, and programs, and outputs the calculation results as control command signals. ing. The input data includes the temperature of the motors 2 and 3, the temperature of the oil that cools the parts to be cooled such as the motors 2 and 3, the oil temperature before and after the oil cooler 23, the temperature of the cooling water of the radiator 22, They are accelerator opening, vehicle speed, wheel speed, remaining charge of the power storage device, and the like. The data stored in advance includes a map that determines each driving mode, a map that determines the optimum fuel consumption line for the engine 1, a map that determines the required power of the engine 1, a map that determines the thermal efficiency of the engine 1, and the like. is. The ECU 24 outputs, as control command signals, a command signal for starting and stopping the engine 1, a torque command signal for the first motor 2, a torque command signal for the second motor 3, a torque command signal for the engine 1, and the like. Although FIG. 1 shows an example in which one ECU 24 is provided, a plurality of ECUs may be provided for each device to be controlled, such as the engine 1 and each of the motors 2 and 3, or for each control content.

The HV travel mode is a travel mode in which the vehicle Ve travels mainly using the engine 1 as a power source, as described above. It is transmitted to the drive wheels 6 . When the power output from the engine 1 is thus transmitted to the drive wheels 6 , the reaction force is applied to the power split mechanism 4 from the first motor 2 . Therefore, the sun gear 8 in the power split device 4 functions as a reaction force element so that the torque output from the engine 1 can be transmitted to the drive wheels 6 . That is, the first motor 2 outputs reaction torque with respect to the engine torque in order to apply torque corresponding to the engine torque to the driving wheels 6 .

Further, the rotation speed of the first motor 2 described above can be arbitrarily controlled according to the current value and its frequency. can be controlled as appropriate or arbitrarily. Basically, the operating point of the engine 1 or the engine speed is controlled so that the first motor 2 optimizes the fuel consumption. That is, the output torque or rotation speed of the first motor 2 is controlled according to the torque transmitted from the engine 1 to the power split device 4 .

In this way, a normal hybrid vehicle is configured to travel mainly in consideration of the thermal efficiency of the engine, that is, with an emphasis on fuel consumption when traveling in the HV traveling mode. On the other hand, if the operating point of the engine 1 is controlled to the operating point where the fuel consumption of the engine 1 is optimal (hereinafter referred to as the optimum fuel consumption line), the fuel consumption is improved, but the motors 2 and 3 and the power split device 4 There is a risk that the amount of heat generated in the transmission 7 that accommodates, for example, may increase. Specifically, as is conventionally known, a motor generates losses such as mechanical loss, iron loss, or copper loss as it is driven, and heat is generated in accordance with these losses. For example, this heat generation raises the temperature of the oil in the transmission 7, which prevents the motor from being cooled, causing the temperature of the motor to rise excessively and possibly reducing the durability of various devices and members.

The above mechanical loss includes, for example, loss due to rotational friction or sliding friction with a bearing caused by the rotation of the rotor shaft 2b of the first motor 2, loss due to friction in each gear of the power split mechanism 4, etc. In addition, this mechanical loss particularly depends on the number of revolutions of the motor. That is, in the HV running mode, the larger the absolute value of the rotation speed of the first motor 2, the larger the mechanical loss. Therefore, in the embodiment of the present invention, the heat generation in the transmission 7 is suppressed by controlling the operating point of the engine 1 in the configuration of the known or existing vehicle Ve. An example of control executed by the ECU 24 will be described below.

FIG. 2 is a flowchart for explaining an example of the control. First, it is determined whether or not the engine 1 is running (step S1). That is, it is determined whether or not the vehicle is traveling in the HV traveling mode using the engine 1 as the power source. Therefore, if the determination in step S1 is negative, that is, if the engine 1 is stopped, such as when the vehicle is traveling in the EV traveling mode, the routine returns without executing the subsequent control.

Conversely, if the determination in step S1 is affirmative, that is, if the vehicle is traveling in the HV traveling mode, then it is determined whether the oil temperature (oil temperature) is equal to or higher than a predetermined threshold temperature α. (step S2). This is a step for determining whether or not the temperature inside the transmission 7 is equal to or higher than a predetermined temperature. , 3 and the power split device 4). Further, by determining the temperature of this oil, it is also possible to determine whether or not the oil cooler 23 can ensure the cooling performance. In normal control, as described above, the engine 1 is controlled along the optimum fuel consumption line, so the engine 1 is controlled with priority given to fuel consumption. On the other hand, if the temperature inside the transmission 7 rises, or if the cooling performance becomes insufficient due to the rise in the temperature inside the transmission 7, the amount of heat generated increases, and the power loss in the transmission 7 may become excessive. That is, in step S2, the engine 1 is normally controlled along the optimum fuel consumption line with priority given to fuel consumption, but the engine 1 is removed from the optimum fuel consumption line in consideration of heat generation and power loss in the transmission 7. It is configured to determine whether or not to control by

One of the parameters for judging the state of heat generation in the transmission 7 is the oil temperature. Further, the threshold temperature α and the predetermined temperature in the transmission 7 are values predetermined by experiments or the like, and may be determined in consideration of the durability of various devices in addition to the power loss described above. . Therefore, if the determination in step S2 is negative, that is, if the oil temperature is less than the threshold temperature α, the process returns without executing subsequent control.

In addition to the temperature of the oil described above, the parameters for determining the heat generation state are assumed to include, for example, the temperature of the motors 2 and 3, the temperature of the oil before and after the oil cooler 23, and the temperature of the cooling liquid of the radiator 22. Predetermined threshold values for judging the heat generation state are also provided for each of these parameters, and if the temperature of each parameter is less than the threshold temperature, similarly the process returns without executing subsequent control. Furthermore, the heat generation state may be determined not only from the current temperature of the oil, but also from the amount of change in the temperature of the oil.

Further, if the determination in step S2 is negative, the amount of heat generated in the transmission 7 is relatively small, or the oil cooler 23 is in a state where the oil can be cooled to an appropriate temperature. is emphasized, and the operating point of the engine 1 is controlled along the optimum fuel efficiency line.

On the other hand, if the determination in step S2 is affirmative, that is, if the oil temperature is equal to or higher than the threshold temperature α, then the threshold β for the required power (or engine required power) at the predetermined vehicle speed is determined (step S3). This threshold value β is a reference value for controlling the operating point of the engine 1, and is determined on the optimum fuel efficiency line, which is the operating point in normal control. In step S2, when it is determined that the oil temperature is equal to or higher than the threshold temperature α, when the engine 1 is controlled along the optimum fuel efficiency line, the transmission 7 or each motor accommodated in the transmission 7 It can be determined that there is a possibility that the amount of heat generated in the parts to be cooled such as 2 and 3 will increase. Regarding the power loss in the transmission 7 when the temperature of the oil is equal to or higher than the threshold temperature α, a map is prepared in advance to indicate which driving point or operating point the engine 1 selects to cause excessive power loss. is stored in the ECU 24. The map is, for example, a graph with engine torque on the vertical axis and engine speed on the horizontal axis. Determine which operating point selection relative to the line is desirable to reduce power loss. Furthermore, such a map is prepared for each vehicle speed (for example, every 20 km/h) and stored in the ECU 24 .

Since the power loss (especially mechanical loss) in the transmission 7 depends on the rotation speed of the first motor 2 as described above, by controlling the rotation speed of the first motor 2 to a low rotation speed range, the transmission 7 It can suppress heat generation inside. Therefore, the threshold value β for the required power is obtained when the number of revolutions of the first motor 2 is controlled to a predetermined low number of revolutions capable of suppressing the heat generation in the transmission 7 and passes the optimum fuel efficiency line. become a point. That is, the threshold β of the required power is the point at which heat generation (power loss) in the transmission 7 can be most suppressed on the optimum fuel efficiency line.

Note that the rotation speed of the first motor 2 capable of suppressing heat generation in the transmission 7 described above is a predetermined low rotation speed range including "0", and the threshold value β , and the higher the vehicle speed with respect to a predetermined vehicle speed, the larger the threshold value β. Then, the threshold value β of the required power for each vehicle speed is stored in advance in the ECU 24 by, for example, mapping the relationship between the engine torque and the engine speed. The required power is obtained based on the required driving force and the vehicle speed, and the required driving force is obtained from, for example, the accelerator opening based on the driver's accelerator operation.

FIG. 3 is a diagram for explaining the operating points (or operating lines) of the engine 1 in the embodiment of the present invention. The threshold β is shown on the optimum fuel efficiency line. Reference character L1 indicates an operating line connecting operating points of optimum fuel efficiency (that is, optimum fuel consumption line), reference character WOT indicates a power line connecting operating points that provide the maximum torque that can be output, reference characters P1, P2, etc. Output lines (P1>P2) are shown. Then, from the map obtained by obtaining the power loss stored in the ECU 24 described above, on the higher power side (right side in FIG. 3) than the threshold value β, the direction in which the engine speed is decreased is the engine where the power loss in the transmission 7 is relatively small. 1 operating point. On the contrary, on the lower power side (left side in FIG. 3) of the threshold value β, it is understood that the direction in which the engine speed is increased is the operating point of the engine 1 at which the power loss in the transmission 7 is relatively small. there is

Next, it is determined whether or not the required power is equal to or greater than the threshold value β determined in step S3 (step S4). This is a step of determining where on the map the operating point of the engine 1 should be selected or determined in order to reduce the power loss in the transmission 7. The operating point of the engine 1 is changed on the basis of the fuel consumption line. That is, the threshold value β described above serves as a reference. Then, when the required power is equal to or greater than the threshold β, the operating point of the engine 1 is selected or determined so as to decrease the engine speed (step S5). That is, when the required power is equal to or greater than the threshold value β as described above (for example, P1 in FIG. 3), the operating point A is selected as the operating point on the optimum fuel efficiency line under normal control. is selected to control the engine 1, the amount of heat generated in the transmission 7 may increase and power loss may increase. Therefore, in order to select the operating point of the engine 1 with relatively little power loss in the transmission 7, the operating point to be selected is changed from the operating point A to the operating point A'. The operating point of the engine 1 is controlled by the first motor 2 as described above, and the rotation speed of the first motor 2 is controlled to a predetermined low rotation speed region close to zero rotation speed.

Further, the operating point of the engine 1 to be selected should preferably have a smaller change in engine power. Therefore, as shown in FIG. 3, the operating point is changed on the iso-output line P1. On the other hand, which operating point is selected on the iso-output line P1 is determined by considering the thermal efficiency of the engine 1 and the power loss in the transmission 7. FIG. FIG. 4 is a map showing the thermal efficiency of a general engine. When the operating point is controlled along the optimal fuel consumption line, the thermal efficiency of the engine is the best, and the operating point outside the optimal fuel consumption line is selected. As the temperature increases, the thermal efficiency decreases. It should be noted that each closed area surrounded by a dashed line indicates an area in which the thermal efficiency is the same.

As described above, the power loss in the transmission 7 is reduced by controlling the engine speed to decrease in step S5. Conversely, the thermal efficiency of engine 1 decreases as it deviates outward from the optimum fuel economy line. Therefore, in determining which operating point to select on the iso-output line P1, the thermal efficiency of the engine 1 and the power loss of the transmission 7 should be taken into consideration, and the energy efficiency of the vehicle Ve as a whole is good. configured to select as the operating point. In the example shown in FIG. 3, the point of intersection between the iso-output line P1 and the maximum torque line WOT is the most optimal operating point A'.

On the other hand, if the determination in step S4 is negative, that is, if the required power is less than the threshold value β, the operating point of the engine 1 is selected or determined in the direction of increasing the engine speed (step S6). That is, when the required power is smaller than the threshold value β as described above (for example, P2 in FIG. 3), normal control selects the operating point B as the operating point on the optimum fuel efficiency line. If the operating point B is selected and the engine 1 is controlled, the amount of heat generated in the transmission 7 may increase and the loss may increase. Therefore, in order to select the operating point of the engine 1 with relatively small loss in the transmission 7, the operating point of the engine 1 to be selected is changed from the operating point B to the operating point B'. As in step S5, this change in operating point is selected by controlling the rotation speed of the first motor 2 in a predetermined low rotation speed range. Similarly, the operating point of the engine 1 to be selected should preferably have a small change in engine power. Therefore, as shown in FIG. The operating point is determined in consideration of the power loss in the transmission 7 . In the example of FIG. 3, the operating point B' is the point where the efficiency of the vehicle Ve as a whole is good.

Thus, in the embodiment of the present invention, when the temperature of the oil is equal to or higher than the threshold temperature α, that is, when it is determined that the temperature inside the transmission 7 is equal to or higher than the predetermined temperature, the amount of heat generated (that is, power loss) is reduced. Therefore, it is arranged to control the operating point of the engine 1 so as to reduce its power loss. Specifically, the operating point of the engine 1, which is normally controlled along the optimum fuel efficiency line, is set to decrease the engine speed when the required power is equal to or greater than the above-mentioned threshold value β. configured to control. Conversely, when the required power is less than the above threshold value β, the operating point of the engine 1 is controlled to increase the engine speed. This operating point of the engine 1 is an operating point at which the power loss in the transmission 7 is reduced, which is obtained from experiments and the like. Power loss in the transmission 7 can be reduced.

Further, the control of the engine speed at the operating point of the engine 1 is controlled by the first motor 2, and the speed of the first motor 2 is controlled in the low speed range. As a result, the rotation speed of the first motor 2 becomes low, so the mechanical loss that depends on the rotation speed of the first motor 2 is reduced, and the amount of heat generated thereby is also reduced. In other words, it is possible to prevent the temperature of various devices such as the motors that contribute to the operation of the first motor 2 and the temperature of the respective parts such as the gears from dropping, thereby suppressing the deterioration of the durability of these devices. Furthermore, by controlling the rotation speed of the first motor 2 to the low rotation speed range as described above, heat generation in the transmission 7 can be suppressed, so an increase in temperature in the transmission 7 can be suppressed. Therefore, it is not necessary to provide a new cooling mechanism or to improve the performance of the currently installed cooling mechanism such as the oil cooler 23 . Therefore, it is possible to suppress or avoid an increase in cost for improving the cooling performance, and in other words, it is possible to secure the cooling performance with the configuration of the existing vehicle Ve.

Further, as described above, the operating point of the engine 1 to be selected is configured to be determined in consideration of the thermal efficiency of the engine 1 and the power loss in the transmission 7. Therefore, the energy efficiency of the vehicle Ve as a whole is can be improved. Furthermore, when the temperature of the oil in the transmission 7 and the temperatures of the motors 2 and 3 are less than the threshold temperature, the operating point of the engine 1 is controlled along the optimum fuel consumption line with emphasis on fuel consumption, as in normal control. is configured to Therefore, according to the hybrid vehicle Ve in the embodiment of the present invention, it is possible to achieve both fuel efficiency and cooling performance.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and may be modified as appropriate within the scope of achieving the object of the present invention. In the above-described embodiment, in order to determine the temperature or heat generation state in the transmission 7 in step S2, the temperature of the oil, the temperature of the motors 2 and 3, the temperature of the coolant in the radiator 22, the temperature of the oil cooler 23, and the Although the front and rear oil temperatures have been described as parameters, each of these parameters may be determined based on at least one parameter. Also, these parameters may be coordinated to determine the temperature or heat generation state within the transmission 7 .

Further, the hybrid vehicle targeted by the present invention may be applied to a vehicle other than the hybrid vehicle Ve shown in FIG. 1. For example, the example shown in FIG. It may be applied to an FR (front engine/rear drive) vehicle in which no differential gear unit is accommodated in the transmission case 7a. Further, for example, the configuration of the power split mechanism 4 described above is not limited to a single pinion type planetary gear mechanism, and may be configured by a double pinion type planetary gear mechanism, or a Ravigneaux gear mechanism having four or more rotating elements. It may be configured with a planetary gear mechanism of the type.

DESCRIPTION OF SYMBOLS 1... Engine (ENG) 2... 1st motor (MG1) 4... Power split mechanism 6... Drive wheel 7... Transmission 7a... Transmission case 8... Sun gear 9... Ring gear 10... Carrier 11... Pinion gear 22 Radiator 23 Oil cooler 24 Controller (ECU) L1 Optimal fuel consumption line P1, P2 Equal output line Ve Vehicle.

Claims (3)

An engine, a first motor, and a transmission that transmits the output torque of the engine to drive wheels,
The transmission includes a first rotating element to which the output torque of the engine is transmitted, a second rotating element connected to the driving wheels so as to transmit torque, and a third rotating element to which torque is transmitted from the first motor. a differential mechanism having at least three rotating elements with a rotating element;
A control device for a hybrid vehicle configured to transmit the output torque of the engine to the driving wheels via the differential mechanism while cooling the inside of the transmission to perform HV running,
A controller that controls the engine and the first motor,
The controller is
controlling the operating point of the engine by controlling the rotation speed of the first motor ,
When a predetermined temperature parameter for determining the state of heat generation inside the transmission is lower than a predetermined temperature during HV running,
controlling the rotation speed of the first motor so that the engine is operated at an operating point at which the fuel efficiency of the engine is the best;
When the temperature parameter is equal to or higher than the predetermined temperature during HV running ,
Prioritizing reduction of heat generation inside the transmission over fuel consumption of the engine, the rotation speed of the first motor is controlled to a predetermined rotation speed range including 0 in which the heat generation can be suppressed. By controlling the operating point of the engine to an operating point that reduces the amount of heat generated ,
When controlling the operating point of the engine to an operating point that reduces the amount of heat generated ,
Finding the required power of the engine,
determining whether the required power is equal to or greater than a predetermined threshold;
When it is determined that the required power is equal to or greater than the threshold, the engine speed is reduced from the operating point at which the fuel efficiency is optimal while satisfying the required power, and change in the direction of increasing the output torque of the engine,
when it is determined that the required power is less than the threshold, the operating point of the engine is increased from the operating point at which the fuel efficiency is optimal while satisfying the required power, and A control device for a hybrid vehicle, characterized in that it is configured to change the output torque of the engine in a decreasing direction. A control device for a hybrid vehicle according to claim 1,
The hybrid vehicle further includes a cooling mechanism for cooling the transmission and the engine,
The controller is
Determining whether the temperature inside the transmission is equal to or higher than the predetermined temperature is determined by selecting the temperature of the first motor, the temperature of oil that cools the first motor and the differential mechanism, and the temperature of the cooling mechanism. A control device for a hybrid vehicle, characterized in that the determination is made based on at least one parameter temperature. A control device for a hybrid vehicle according to claim 1 or 2,
The control device for a hybrid vehicle, wherein the threshold value is set to be larger at a high vehicle speed than at a predetermined vehicle speed.

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